1. Field of the Invention
The present invention relates to high-end pattern generation, such as for the patterning of photomasks, microelectronic and microoptical devices and for production of display devices. Other applications of highly precise patterns such as security printing and interconnection devices are also related to the invention.
The term pattern generator is used in the description to mean a machine that creates a physical pattern from data, typically by the action of light on a photosensitive surface.
2. Description of Related Art
Patterning of photomasks for the production of integrated circuits is developing according to the so-called More's law, where every three years a new circuit generation with four times the complexity of the previous one is created. Thirty-five years ago the patterns were manually cut with knife in a red plastic film, so called Rubylith film. Later, the need for increasingly precise and complex patterns led to the development of the optical pattern generator with a computer-controlled stage and flash lamp that exposed a series of rectangles on emulsion film. In the mid eighties the e-beam and optical raster-scanning pattern generators were invented and have since provided masks with astounding accuracy and feature density. However, being in principle serial devices, the raster scanning pattern generators are approaching their end of economic life. What is needed is a radically new writing principle that can keep up with the exponential growth of complexity predicted by More's law.
In a series of pending PCT patent applications (SE99/00310 and others) one of the inventors (Sandström) has disclosed a novel type of pattern generator with advantages in resolution, precision and throughput over any other previously known systems. The present invention is a data path with extremely high data capacity to be used in this new type of pattern generator. Another aspect of the invention is the provisions for calibrations and real-time data corrections that make the new pattern generator highly precise even at very high speeds.